Granular material is typically held in storage chambers until use. The ability of the material to flow through the exit orifice of the chamber depends in large part upon the particle size, shape and moisture content. The typical funnel shape of the storage chamber, along with gravity helps facilitate the flow of the material, and for most granular material that is enough. An excellent example of free-flowing material is sand. Fine powders, on the other hand, are much more resistant to flow due to their cohesive nature and/or bulk density and consequently need more than just the help of gravity to keep them flowing. An excellent example is baking flour, which is very resistant to flow and consequently needs the scraping action of a “flour sifter” to exit its chamber. In an effort to achieve a steady, even flow of material, the most common method of solving this flow problem is vibrating and/or pressurizing the entire storage chamber. However, there are still some powders that will not flow evenly, even with the use of vibration and air pressure. As a result, the phenomena of caking, bridging and rat holing are often seen in fine powders.
Referring now to FIG. 1, there is shown three prior art diagrams illustrating the phenomena of caking, bridging and rat holing that fine powders often exhibit. Caking occurs when a large amount of powder sticks to the sides of the chamber, and refuses to flow downward. Bridging occurs when the powder forms a bridge over the exit orifice, and effectively prevents the flow of material entirely. Rat holing occurs when a channel forms down the middle of the chamber, and a large amount of powder is left clinging to the sides of the chamber. In general, each of these three problems is seen at the entrance to the exit orifice.
Accordingly, there is a need for a flow facilitator that addresses the above-described problem phenomena often encountered at the entrance to the exit orifice.